Up to 22 prisoners will be transferred to Symonston Correctional Facility, which was redeveloped to take overflow when the chronically overcrowded Alexander Maconochie Centre reached capacity.

Justice Minister Shane Rattenbury said a "small, carefully selected cohort of detainees" would be transferred to the facility from Thursday.

The Symonston centre, which sits on Mugga Lane, was previously only used for weekend detention until the government spent $60,000 on upgrades to allow for full-time detention.

Mr Rattenbury announced in April the temporary prison would provide an extra 22 beds to help authorities cope with inmate numbers until permanent upgrades were ready at the prison.

Thursday's announcement was met with displeasure from local community representatives, who previously complained about the lack of warning and said Symonston had become a "dumping ground" for the government's controversial facilities.

But Inner South Canberra Community Council chair Gary Kent thanked Mr Rattenbury for notifying residents, and acknowledged the minister was doing his best to deal with an overcrowding crisis not of his making.

Residents of Symonston, Red Hill, Narrabundah, and Griffith were sent letters about the matter in April

Mr Kent, however, said residents would be watching and waiting to ensure the government kept its word that the full-time Symonston facility would be used as a stop-gap only.

"We're not happy about it, but we acknowledge that given the Alexander Maconochie Centre was too small, the government really didn't have any other option," he said.

"If anywhere else in Canberra a jail was erected across the road, there'd be an uproar.

"So the people near Symonston are very patient and we have no reason not to believe [Mr Rattenbury's] assurances at this point."

Opposition corrections spokesman Andrew Wall still had major concerns about security at the Symonston centre.

"This is an old facility that was earmarked for closure as a periodic detention centre, now being retro-fitted as a full-time custodial centre.

"What surveillance is available, what healthcare is available, what other crisis support is there should it be needed if it is normally available at the AMC?"

"I think it's right that the community has got some concerns about what measures have been put in place given this facility is now being retro-fitted for a purpose it was never intended for."

Mr Rattenbury said the facility would be used "as little as possible".

He said detainees would be individually assessed by ACT Corrective Services and only low-risk prisoners would be moved there.

"Residents can be assured that there are appropriate security measures in place, including CCTV and a secure perimeter."

"It is intended to be short term, this is not a permanent facility it's very much about provided some extra capacity until the new parts of the AMC are completed from the construction phase.

The ACT's prison opened in 2009 and has been under pressure from a rapidly increasing detainee population since 2013.

A temporary expansion increased capacity from 332 beds to about 370, while an urgent and major permanent upgrade was launched to add an extra 110 beds by mid-2016. The first 30 of those beds are expected to be ready by the second half of this year.

But overcrowding has reached critical levels again and the jail consistently houses 350 detainees or more.